The offer's limited to owners of the gadgets listed above, as well as the iPhone 6 and iPhone 6 Plus, who also happen to have a MasterCard credit or debit card hooked up to Apple Pay. It’s also only valid on the four Mondays that fall between 23 November and 14 December, and you can claim a maximum of £27.90 altogether. Here are the terms and conditions.

However, it’s still a tasty deal, especially as it applies to London's buses, the Underground, trams, the DLR, London Overground, the Emirates Air Line, and a selection of the capital's National Rail services. The only real downside is that you might end up looking like a bit of a prat if your flash phone or watch gets stage fright and fails to touch you in, leading to you pissing off a load of irritable fellow commuters.